Dosing module

Abstract

A dosing module for an emissions abatement system, the dosing module including an armature, means for moving the armature and a valve body having an outlet; the dosing module having an unblocked condition, in which the armature is moveable between a first position, in which the outlet is closed by the armature, and a second position, in which the armature is spaced apart from the outlet, and wherein, in use, application of electricity to the means for moving the armature at a first level of energy causes the armature to move from the first position to the second position; the dosing module further having a blocked condition, in which flow of a liquid through the outlet is prevented, wherein, in use, application of electricity to the means for moving the armature at a second level of energy causes the dosing module to change to the unblocked condition.

What is claimed is: 
     
       1. A method of operating a dosing module for an emissions abatement system, the dosing module including an armature, a coil for moving the armature and a valve body having an outlet, wherein in normal operation the armature is moveable between a first position, in which the outlet is closed by the armature, and a second position, in which the armature is spaced apart from the outlet, and wherein, in use, application of electricity to the coil at a first level of energy causes the armature to move from the first position to the second position, the method comprising:
 (a) determining that the dosing module is in a blocked condition; 
 (b) increasing the temperature of the dosing module by applying electricity at a second level of energy that is greater than the first level of energy to the coil; and 
 (c) heating the dosing module until the dosing module is in an unblocked condition, in which liquid can flow through the dosing module, the method further comprising at least one or more of: 
 (d) operating the dosing module to pass liquid through the dosing module, and/or wherein the step of determining that the dosing module is in a blocked condition includes determining that flow of a liquid through the dosing module is prevented and/or wherein the step of determining that the dosing module is in a blocked condition includes: 
 (i) determining a first pressure of a liquid to be supplied by the dosing module prior to actuation of the dosing module; 
 (ii) determining a second pressure of a liquid to be supplied by the dosing module during actuation of the dosing module; and 
 (iii) comparing the first pressure and the second pressure, for example wherein, in step (iii) the second pressure is greater than the first pressure. 
 
     
     
       2. A method of operating a dosing module according to  claim 1 , wherein the step of increasing the temperature of the dosing module by applying electricity to the dosing module includes increasing the temperature to at least 100° C., and further comprises at least one of: increasing the temperature of the dosing module by applying electricity to the dosing module and holding the increased temperature for less than 400 seconds by applying electricity to the dosing module by applying an electrical current to the dosing module of at least 400 milliamps. 
     
     
       3. A method of operating a dosing module according to  claim 1 , wherein the liquid includes a reductant including at least one of: wherein the liquid includes urea, wherein the liquid includes Diesel Exhaust Fluid, or wherein the liquid includes AdBlue. 
     
     
       4. A method of operating a dosing module according to  claim 1 , wherein, when the dosing module is in the blocked condition, flow of a liquid through the outlet is prevented by crystals of the liquid. 
     
     
       5. A method of operating a dosing module according to  claim 2 , wherein increasing the temperature of the dosing module by applying electricity to the dosing module includes holding the increased temperature for less than 200 seconds. 
     
     
       6. A method of operating a dosing module according to  claim 2 , wherein increasing the temperature of the dosing module by applying electricity to the dosing module includes applying an electrical current to the dosing module of at least 500 milliamps.